I can't believe it took me this long to learn this, so I'm sharing it with everyone:
You can Shift-Control-click to add more than one item's worth of components into your quick-buy list. Yes, it's true. You can add a stick+boots+ward+whatever into the same list. Keep in mind that whatever you add first will appear first, so items like the Orchid will consume all the available viewing space if you add it first.
... I'm ashamed I didn't know this by now.